1. Field of the Invention
The present invention relates to a fingerprint recognition technique and, more particularly, to an apparatus and method for fingerprint recognition with continued updating of a reference user fingerprint.
2. Description of the Related Art
As mobile terminals are becoming more popular, sending and receiving sensitive or confidential information using mobile terminals is increasing. An example would be performing various financial transactions via a mobile phone (i.e., “mobile banking”). Such features related to user privacy and transmitting sensitive information require more advanced user authentication techniques. As such, mobile terminal manufacturers are providing security functions for mobile terminals by using biometrics authentication.
Typical biometrics authentication techniques include fingerprint recognition and iris recognition. Currently, fingerprint recognition is commonly implemented in mobile terminals.
Fingerprint recognition is a technique whereby the user places or swipes his finger on a fingerprint recognition apparatus (i.e., fingerprint sensor or reader). In general, two types of methods may be employed: the first is a total internal reflection method in which an image of the fingerprint is reflected by applying as intense light thereto for conversion into an electrical signal, and the second is a silicon chip sensing method in which a particular pattern of a fingerprint is read as an electrical signal by using electrical conduction characteristics of the user's finger that is placed or swiped.
In order to implement fingerprint authentication in a mobile terminal, a reference (or standard or ‘comparison model’) fingerprint of the user should be registered in the fingerprint recognition apparatus. To do so, the fingerprint recognizing apparatus may request the user to repeatedly scan his finger (or fingers) several times over a fingerprint sensor or other type of detecting means. Based upon these scans, a reference fingerprint can be created (by combining portions of multiple fingerprint scans) and stored, or the “best” (i.e., most accurately) scanned fingerprint among the multiple scans can be selected and stored.
Once the comparison model of the user fingerprint is determined and stored, the fingerprint recognizing apparatus performs a fingerprint recognition procedure by comparing a currently scanned fingerprint with the comparison model to thus determine whether the user has authorization.
FIG. 1 is a flow chart illustrating an exemplary process of a fingerprint recognition procedure for a mobile terminal in accordance with a related art.
When the mobile terminal is in an operation locked state, the fingerprint recognizing apparatus requests the user to place or swipe his finger(s) on an input device of the mobile terminal when the user attempts to use the mobile terminal. Then, the fingerprint(s) of the user is scanned through a fingerprint sensor (step S10).
The scanned fingerprint is compared with the registered comparison model (i.e., the reference fingerprint of an authorized user) (step S20), and when the scanned fingerprint is deemed sufficiently identical to the reference fingerprint, the lock function of the mobile terminal is released (step S60).
However, if the scanned fingerprint is deemed not sufficiently identical to the reference fingerprint, the mobile terminal informs the user that authorization has failed and may repeatedly perform the steps S10 and S20.
When more than a certain number of fingerprint recognition failures occur (e.g., three times) (step S40), the mobile terminal releases the fingerprint security function and requests the user to input a password. And then, the mobile terminal compares an inputted password with a previously stored password to determine whether to release the lock function previously set in the mobile terminal (step S50).
In the related art fingerprint recognizing apparatus of the mobile terminal, a sufficient number of fingerprint scans must be ideally performed in order to obtain enough fingerprint data to allow subsequent fingerprint recognition to be performed accurately. However, in most related art fingerprint authorization systems, in order to minimize user inconvenience, the comparison model of the user fingerprint is generated through a simplified procedure (such as obtaining only a minimum number of fingerprint scans), which leads to degraded reliability of fingerprint authentication. In addition, since the finger placement or swiping performed by the user when actually attempting to access the mobile terminal may be inconsistent (e.g., different speeds at which the user swipes his finger, different amounts of pressure applied when pressing down his finger, etc.), the success rate of accurate fingerprint recognition is undesirably too low.
In addition, when fingerprint recognition is deemed unsuccessfully after more than a certain number of failed attempts, the related art mobile terminal releases the security function provided by the fingerprint recognition feature, and instead, user authentication is performed through password inputting. As such, the related art fingerprint recognizing apparatus does not substantially use the security function based upon fingerprint recognition. Thus, the related art fingerprint recognition technique for a mobile terminal can be easily by-passed or avoided by unauthorized users who may access the mobile terminal by using password information obtained in an unauthorized manner from the rightful user.